linux/kernel/irq, branch v3.4.96

genirq: Sanitize spurious interrupt detection of threaded irqs

2014-07-01T03:01:33Z

commit 1e77d0a1ed7417d2a5a52a7b8d32aea1833faa6c upstream. Till reported that the spurious interrupt detection of threaded interrupts is broken in two ways: - note_interrupt() is called for each action thread of a shared interrupt line. That's wrong as we are only interested whether none of the device drivers felt responsible for the interrupt, but by calling multiple times for a single interrupt line we account IRQ_NONE even if one of the drivers felt responsible. - note_interrupt() when called from the thread handler is not serialized. That leaves the members of irq_desc which are used for the spurious detection unprotected. To solve this we need to defer the spurious detection of a threaded interrupt to the next hardware interrupt context where we have implicit serialization. If note_interrupt is called with action_ret == IRQ_WAKE_THREAD, we check whether the previous interrupt requested a deferred check. If not, we request a deferred check for the next hardware interrupt and return. If set, we check whether one of the interrupt threads signaled success. Depending on this information we feed the result into the spurious detector. If one primary handler of a shared interrupt returns IRQ_HANDLED we disable the deferred check of irq threads on the same line, as we have found at least one device driver who cared. Reported-by: Till Straumann Signed-off-by: Thomas Gleixner Tested-by: Austin Schuh Cc: Oliver Hartkopp Cc: Wolfgang Grandegger Cc: Pavel Pisa Cc: Marc Kleine-Budde Cc: linux-can@vger.kernel.org Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1303071450130.22263@ionos Signed-off-by: Greg Kroah-Hartman

genirq: Remove racy waitqueue_active check

2014-03-24T04:37:05Z

commit c685689fd24d310343ac33942e9a54a974ae9c43 upstream. We hit one rare case below: T1 calling disable_irq(), but hanging at synchronize_irq() always; The corresponding irq thread is in sleeping state; And all CPUs are in idle state; After analysis, we found there is one possible scenerio which causes T1 is waiting there forever: CPU0 CPU1 synchronize_irq() wait_event() spin_lock() atomic_dec_and_test(&threads_active) insert the __wait into queue spin_unlock() if(waitqueue_active) atomic_read(&threads_active) wake_up() Here after inserted the __wait into queue on CPU0, and before test if queue is empty on CPU1, there is no barrier, it maybe cause it is not visible for CPU1 immediately, although CPU0 has updated the queue list. It is similar for CPU0 atomic_read() threads_active also. So we'd need one smp_mb() before waitqueue_active.that, but removing the waitqueue_active() check solves it as wel l and it makes things simple and clear. Signed-off-by: Chuansheng Liu Cc: Xiaoming Wang Link: http://lkml.kernel.org/r/1393212590-32543-1-git-send-email-chuansheng.liu@intel.com Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

genirq: Add missing irq_to_desc export for CONFIG_SPARSE_IRQ=n

2014-02-22T18:32:46Z

commit 2c45aada341121438affc4cb8d5b4cfaa2813d3d upstream. In allmodconfig builds for sparc and any other arch which does not set CONFIG_SPARSE_IRQ, the following will be seen at modpost: CC [M] lib/cpu-notifier-error-inject.o CC [M] lib/pm-notifier-error-inject.o ERROR: "irq_to_desc" [drivers/gpio/gpio-mcp23s08.ko] undefined! make[2]: *** [__modpost] Error 1 This happens because commit 3911ff30f5 ("genirq: export handle_edge_irq() and irq_to_desc()") added one export for it, but there were actually two instances of it, in an if/else clause for CONFIG_SPARSE_IRQ. Add the second one. Signed-off-by: Paul Gortmaker Cc: Jiri Kosina Link: http://lkml.kernel.org/r/1392057610-11514-1-git-send-email-paul.gortmaker@windriver.com Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

irq: Enable all irqs unconditionally in irq_resume

2013-12-12T06:34:11Z

commit ac01810c9d2814238f08a227062e66a35a0e1ea2 upstream. When the system enters suspend, it disables all interrupts in suspend_device_irqs(), including the interrupts marked EARLY_RESUME. On the resume side things are different. The EARLY_RESUME interrupts are reenabled in sys_core_ops->resume and the non EARLY_RESUME interrupts are reenabled in the normal system resume path. When suspend_noirq() failed or suspend is aborted for any other reason, we might omit the resume side call to sys_core_ops->resume() and therefor the interrupts marked EARLY_RESUME are not reenabled and stay disabled forever. To solve this, enable all irqs unconditionally in irq_resume() regardless whether interrupts marked EARLY_RESUMEhave been already enabled or not. This might try to reenable already enabled interrupts in the non failure case, but the only affected platform is XEN and it has been confirmed that it does not cause any side effects. [ tglx: Massaged changelog. ] Signed-off-by: Laxman Dewangan Acked-by-and-tested-by: Konrad Rzeszutek Wilk Acked-by: Heiko Stuebner Reviewed-by: Pavel Machek Cc: Cc: Cc: Cc: Link: http://lkml.kernel.org/r/1385388587-16442-1-git-send-email-ldewangan@nvidia.com Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

genirq: Fix can_request_irq() for IRQs without an action

2013-07-22T01:19:01Z

commit 2779db8d37d4b542d9ca2575f5f178dbeaca6c86 upstream. Commit 02725e7471b8 ('genirq: Use irq_get/put functions'), inadvertently changed can_request_irq() to return 0 for IRQs that have no action. This causes pcibios_lookup_irq() to select only IRQs that already have an action with IRQF_SHARED set, or to fail if there are none. Change can_request_irq() to return 1 for IRQs that have no action (if the first two conditions are met). Reported-by: Bjarni Ingi Gislason Tested-by: Bjarni Ingi Gislason (against 3.2) Signed-off-by: Ben Hutchings Cc: 709647@bugs.debian.org Link: http://bugs.debian.org/709647 Link: http://lkml.kernel.org/r/1372383630.23847.40.camel@deadeye.wl.decadent.org.uk Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

genirq: Avoid deadlock in spurious handling

2013-02-28T14:58:58Z

commit e716efde75267eab919cdb2bef5b2cb77f305326 upstream. commit 52553ddf(genirq: fix regression in irqfixup, irqpoll) introduced a potential deadlock by calling the action handler with the irq descriptor lock held. Remove the call and let the handling code run even for an interrupt where only a single action is registered. That matches the goal of the above commit and avoids the deadlock. Document the confusing action = desc->action reload in the handling loop while at it. Reported-and-tested-by: "Wang, Warner" Tested-by: Edward Donovan Cc: "Wang, Song-Bo (Stoney)" Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

genirq: Always force thread affinity

2013-01-11T17:06:56Z

commit 04aa530ec04f61875b99c12721162e2964e3318c upstream. Sankara reported that the genirq core code fails to adjust the affinity of an interrupt thread in several cases: 1) On request/setup_irq() the call to setup_affinity() happens before the new action is registered, so the new thread is not notified. 2) For secondary shared interrupts nothing notifies the new thread to change its affinity. 3) Interrupts which have the IRQ_NO_BALANCE flag set are not moving the thread either. Fix this by setting the thread affinity flag right on thread creation time. This ensures that under all circumstances the thread moves to the right place. Requires a check in irq_thread_check_affinity for an existing affinity mask (CONFIG_CPU_MASK_OFFSTACK=y) Reported-and-tested-by: Sankara Muthukrishnan Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1209041738200.2754@ionos Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

random: remove rand_initialize_irq()

2012-08-15T15:10:29Z

commit c5857ccf293968348e5eb4ebedc68074de3dcda6 upstream. With the new interrupt sampling system, we are no longer using the timer_rand_state structure in the irq descriptor, so we can stop initializing it now. [ Merged in fixes from Sedat to find some last missing references to rand_initialize_irq() ] Signed-off-by: "Theodore Ts'o" Signed-off-by: Sedat Dilek Signed-off-by: Greg Kroah-Hartman

random: make 'add_interrupt_randomness()' do something sane

2012-08-15T15:10:10Z

commit 775f4b297b780601e61787b766f306ed3e1d23eb upstream. We've been moving away from add_interrupt_randomness() for various reasons: it's too expensive to do on every interrupt, and flooding the CPU with interrupts could theoretically cause bogus floods of entropy from a somewhat externally controllable source. This solves both problems by limiting the actual randomness addition to just once a second or after 64 interrupts, whicever comes first. During that time, the interrupt cycle data is buffered up in a per-cpu pool. Also, we make sure the the nonblocking pool used by urandom is initialized before we start feeding the normal input pool. This assures that /dev/urandom is returning unpredictable data as soon as possible. (Based on an original patch by Linus, but significantly modified by tytso.) Tested-by: Eric Wustrow Reported-by: Eric Wustrow Reported-by: Nadia Heninger Reported-by: Zakir Durumeric Reported-by: J. Alex Halderman Signed-off-by: Linus Torvalds Signed-off-by: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman

genirq: export handle_edge_irq() and irq_to_desc()

2012-05-15T15:10:07Z

Export handle_edge_irq() and irq_to_desc() to modules to allow them to do things such as __irq_set_handler_locked(...., handle_edge_irq); This fixes ERROR: "handle_edge_irq" [drivers/gpio/gpio-pch.ko] undefined! ERROR: "irq_to_desc" [drivers/gpio/gpio-pch.ko] undefined! when gpio-pch is being built as a module. This was introduced by commit df9541a60af0 ("gpio: pch9: Use proper flow type handlers") that added __irq_set_handler_locked(d->irq, handle_edge_irq); but handle_edge_irq() was not exported for modules (and inlined __irq_set_handler_locked() requires irq_to_desc() exported as well) Signed-off-by: Jiri Kosina Signed-off-by: Linus Torvalds